VoIP, or Voice over Internet Protocol, is a type of transmissions medium that is responsible for the delivery of real-time voice and data communication. Unlike its analog predecessor in which the transport functionality was routed via the public switched telephone network (PSTN), calls are now converted from an analog signal to a digital format, which is what the Internet Protocol (IP) uses for transmission and delivery, making VoIP possible. Several other key processes, such as signaling, authentication, security, call control, and voice compression, are established by VoIP prior to and during the call setup phase.
The evolution of VoIP is certainly an amazing one, starting back in 1995 when a company called VocalTec Communications released what is believed to be the world’s first Internet software phone product, called Internet Phone. This software was designed to run on home computers very much like the softphone PC clients of today. Telephone calls were made in a peer-to-peer fashion (PC to PC) and utilized earlier adopted VoIP protocols such as H.323. Although VocalTec had a great deal of success as a pioneer in this new area of telecommunications, the technology had several drawbacks. A major drawback was the lack of broadband availability. At that time, the use of lower-speed modems was highly prevalent, and the infrastructure was not in place to support the much needed bandwidth and higher transmission rate requirements. Quality of service was also a huge deterrent. The advancements made in modern codec and audio compression technologies just were not there in the past. The combination of using voice communication in conjunction with the slower modem technology resulted in serious voice quality concerns.
With the emergence of broadband along with the continued innovation in VoIP development, protocol standardization and formality started to arise. Superior advancements in routing and switching with emphasis on QoS control and packet priority aided in building the next-generation VoIP platform of today. Notably, despite the expansive growth of VoIP, security considerations were very limited. With this increased momentum, VoIP as a mainstream offering became the premiere product choice of telcos such as Sprint, Verizon, AT&T, Comcast, and so forth, which viewed it as a highly lucrative and low-cost mechanism for residential and business customers. This in itself created a new type of competition and marketing mix, with various flavors of service offerings and price point differentiators to meet the needs of many potential clients.
The migration from legacy (analog) type service to VoIP (packet switched) type service has continued growing at a substantial rate. As seen today, the overall subscription cost for VoIP is considerably lower than the subscription cost for its legacy companion. With VoIP, fees are geared toward being flat and fee-based, including both local and long distance, while legacy lines still prove to be quite costly. More importantly, the improvement in voice intelligibility and call quality definitely has made it a worth-while candidate. Thus, the answer to the question “What is VoIP?” could reasonably be that it is the marriage of many complex protocols for use in the exchange of real-time communication for both voice and data communication.